Category Archives: Plants

What Have We Here?

Lichen on branches at the Lower Nine Mile Run Trail near Duck Hollow, 29 Oct 2019 (photo by John Bauman)

What have we here?

Lichens are two organisms that operate as one, a symbiotic partnership of a fungus with a green or blue-green algae (sometimes all three).  The algae’s photosynthesis feeds the fungus.  The fungus gathers and retains water and nutrients and protects the algae.

Those that grow on trees are epiphytes, totally dependent on the surrounding air and precipitation for their nutrition.  As they take in air, their tissues absorb suspended elements in concentrations that mimic the air quality.

Lichens can thrive in some of the harshest habitats on earth but epiphytes can’t live in the presence of air pollution, so we were really surprised to find them on our Duck Hollow walk on 29 October 2019 when the air smelled of rotten eggs.

The smell is hydrogen sulfide from US Steel’s Clairton Coke Works, 8 miles away. On cold calm days the pollution creeps up the Mon Valley and blankets Pittsburgh’s East End, a reminder of Pittsburgh’s Smoky City days.

The pollution happens all too frequently, as shown in these screenshots from on 28 and 29 Oct 2019. (SmellPGH is a crowd-sourced app for reporting air pollution smells. Many dark red triangles mean the air smelled really bad that day. Click here for more info.)

On the day before our walk the air was really bad, 28 Oct 2019 (screenshot from SmellPGH of 28 Oct 2019)
During our 29 October walk the worst smells were near the Mon River (screenshot from SmellPgh of 29 Oct 219)

We can smell hydrogen sulfide but not two dangerous air pollutants that travel with it: sulfur dioxide and particulate. Fructose lichens — the kind that stand out from the branch like those shown above — cannot survive in the presence of sulfur dioxide.

We were amazed. What have we here?

(photos by John Bauman, screenshots from; click on the captions to see the SmellPGH website)

A Brief Change Of Scene

The view from Fort Hill at Cape Cod, 18 Oct 2019 (photo by Kate St. John)

Travel is a tonic for seeing the world in new ways. This month my husband and I spent a week with his sister at Cape Cod where we had new weather, new scenery and new looks at plants I might have seen at home.

Our timing was pretty good. We missed the October 12 nor’easter but were on hand for the October 17 “bomb cyclone.” We didn’t lose power, but it was still very windy on the 18th when I visited Fort Hill, pictured above.

Birds were hard to find that day so I noticed plants such as this European spindle-tree (Euonymous europaeus) with puffy, pink, four-sided fruits.

European spindle-tree fruits, 18 Oct 2019, Dennis, MA (photo by Kate St. John)

The puffballs are actually a casing that holds orange fruit within. This ornamental has probably been planted in Pittsburgh, though I’ve never noticed it.

Euonymous europaeus fruits burst open (photo from Wikimedia Commons)

My favorite discovery was a hole in a leaf.

Someone ate this, Cape Cod, 20 Oct 2019 (photo by Kate St. John)

Who ate it? Perhaps this caterpillar did. I found him elsewhere on the plant.

And finally, the sun touched translucent red berries and made them glow at Bell’s Neck.

The small plants have a single leaf midway up the stem (lefthand photo) and were growing among pine needles. I wonder if they are orchids … Perhaps green adder’s mouth (Malaxis unifolia)? Please leave a comment to tell me what they are.

(photos by Kate St. John except where noted in the captions; click the captions to see the originals)

October Plants

Japanese barberry, Moraine State Park, 13 Oct 2019 (photo by Kate St. John)

October weather is here and the trees are starting to change color in southwestern Pennsylvania. On the ground I found additional evidence of autumn last weekend.

Above, the shiny red fruits of Japanese barberry (Berberis thunbergii) hang from thorny branches. Watch out if you approach them, not because of the thorns but because of ticks. This invasive shrub creates thickets with the perfect micro-climate for black-legged ticks and their favorite host, white-footed mice.

Burdock, nature’s velcro, is still in bloom. The tiny hooks coating the sepal will soon dry out and cling to your clothes as you pass by.

Burdock still blooming, Moraine State Park, 13 October 2019 (photo by Kate St. John)

Though burdock (Arctium minus) is an alien invasive, a local insect has found it tasty. Notice the trail of the leaf miner, highlighted below.

Burdock with leaf miner activity, 13 Oct 2019 (photo by Kate St. John)

Meanwhile a native plant called Lycopodium or groundpine is in autumn dispersal mode. It has sent up tall pale green structures called strobili that will release the plant’s spores(*).

Lycopodium, Moraine State Park, 13 Oct 2019 (photo by Kate St. John)

Lycopodium is a very ancient plant. It’s the last living relative of Lepidodendron, a mighty tree that predates the dinosaurs.

(photos by Kate St. John)

(*) Spores definition from Google dictionary: Spores are minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans.

Fluff Is Ready to Fly

Milkweed pods bursting open (photo by Kate St. John)

At this time of year milkweed pods burst open and the seeds disperse, carried on the wind by sprigs of fluff.

The fluff doesn’t look aerodynamic so how does the the seed stay airborne for so long? Recent studies explaining the flight properties of dandelion fluff may provide a clue for milkweed. Let’s look at dandelions.

Each dandelion seed is attached to parachute-like bit of fluff called a pappus. They look like this before they leave on their journey.

Dandelion fluff (photo by Kate St. John)

When a seed lets loose it dangles below the pappus and floats on the breeze for seven (7) feet or several miles. The goal is for the seed to land far from the parent plant.

Dandelion seeds floating (photo from Wikimedia Commons)

In experiments in 2018, published in the journal Nature, researchers at the University of Edinburgh found that each pappus creates a separated vortex ring on the downwind side that keeps the seed aloft. This video shows how it works.

Read more in Dandelion Seeds Reveal A New Form of Aerodynamics in IFLScience.

Milkweed fluff is not the same shape as dandelions’ so a different mechanism may be at work.

The secrets behind nature’s small flying objects may help us design our own.

(photos by Kate St. John except … floating dandelion seeds are from Wikimedia Commons; click on the caption to see the original.)

Who Made These Holes?

Empty black walnut shell with holes (photos by Kate St. John)

This nutshell is empty and carved with large holes. Their shape and placement tell us who made them.

In the autumn black walnuts ripen and fall from the trees. They’re covered in yellow-green husks that exude a black stain when you open them.

Black walnut in husk, Schenley Park, 27 Sep 2019 (photo by Kate St. John)

Squirrels don’t care about the stain. They chew off the husk and gnaw the wooden shell.

Fox squirrel making the sawdust fly as he opens a black walnut (photo by Donna Foyle)
Fox squirrel chisels a black walnut (photo by Donna Foyle)

They make four holes, two on each side of the shell. The side that opens quickly is gnawed into one large hole. By their shape you can tell that a squirrel ate the nutmeat.

This fox squirrel gnawed a black walnut in Donna Foyle’s backyard in 2014. Find out how long it took him in How To Open A Black Walnut.

(photos by Kate St. John and Donna Foyle, per the captions)

Confusing Fall Asters

Asters, Raccoon Creek State Park, Lake Trail, 27 Sep 2019 (photo by Kate St. John)

It’s late September and asters are blooming throughout western Pennsylvania. I found several patches of purple asters yesterday on the Lake Trail at Raccoon Creek State Park.

These two may be the same species. They have similar leaves and their colors matched in real life though the camera shows them differently. It’s a trick of the light. Cameras are notorious for distorting purple / blue.

Asters, Raccoon Creek State Park, Lake Trail, 27 Sep 2019, 12.18p

I haven’t identified these flowers. My Newcomb’s Wildflower Guide has 10 densely packed pages of asters and that’s not all possible species.

Do you think fall warblers are confusing? Asters (and goldenrods) are the last frontier!

(photos by Kate St. John)

Shaggy Mane

Shaggy mane mushrooms at Black Moshannon State Park, 11 Sept 2019 (photo by Kate St. John)

Last weekend my friend Debbie and I traveled to Williamsport for the annual Pennsylvania Society for Ornithology (PSO) meeting. Along the way we stopped at Black Moshannon State Park where we found these mushrooms disintegrating near the parking lot. Mushrooms are a mystery to me. An expert at the meeting told us what they were.

Shaggy mane mushrooms, also called shaggy ink cap (Coprinus comatus), are a common mushroom in lawns and waste places. Their caps begin as white cylinders, turn shaggy and bell shaped, liquefy into black ink and drip from the edges, eventually disintegrating into an inky blob.

The shaggy manes at Black Moshannon were all dripping black ink so we had no idea they went through the life stages shown in the Wikimedia photo below.

Old and young shaggy mane mushrooms (photo from Wikimedia Commons)

When they’re disintegrating shaggy manes look very unappetizing but according to Wikipedia they are edible when young. However they are frequently confused with a poisonous North American mushroom called the ‘vomiter’ mushroom Chlorophyllum molybdites. Enough said!

p.s. PSO‘s annual September meeting is a great opportunity to go birding in a new-to-you place in Pennsylvania. The outings are led by local birders who know the area well. I visited Montour Preserve and Ricketts Glen State Park last weekend. It was well worth the trip. Next year’s meeting will be in Lancaster County.

Goldenrod In Stages

Goldenrod is going through its paces this month. Here are a few of the stages you’ll see in a native of Pennsylvania, Canada goldenrod (Solidago canadensis).

Buds like these may be hard to find in September because …

Goldenrod buds (photo from Wikimedia Commons)

… Goldenrod is in full bloom.

Flower plume of Solidago canadensis (photo from Wikimedia Commons)

Insects are busily fertilizing the flowers this month. By late September they’ll dry out and develop seeds.

Goldenrod in late September, after flowering (photo from Wikimedia Commons)

In October the seeds are ready to blow on the wind.

Goldenrod gone to seed, October 2016 (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)

Ahhh Chooo!

Common ragweed flower head (photo from Wikimedia Commons)

Ragweed season officially began August 15 and runs through September. I’m not allergic to it, but those of you who are may want to know the enemy and learn how to avoid it.

First, a primer on what is NOT ragweed.

Goldenrod is not ragweed. Ragweed (Ambrosia sp. on left) is a wind-pollinated plant with green flowers on thin spikes. Goldenrod (Solidago sp. on right) is a bee-and-butterfly pollinated plant with yellow flowers in a feathery plume. Don’t worry about those yellow flowers. Goldenrod is not busy spreading pollen; it’s busy attracting bees.

Ragweed (on left) and goldenrod (on right), photos from Wikimedia Commons

Ragweed (Ambrosia genus) is a member of the Aster family native to the Americas but now spread to Europe. The most common species in Pennsylvania, common ragweed Ambrosia artemisiifolia, grows easily by the side of the road and in disturbed places. It doesn’t stand out.

Common ragweed’s female flowers are nearly hidden in the leaf axils and pollinated by the wind.

The male flowers are the ones to worry about. Perched on spikes, facing downward, and loaded with pollen, a slight tap is all it takes to release a cloud of pollen. Imagine what the wind can do!

Closeup of male ragweed flowers in the field (photo from Wikimedia Commons)

A single plant may produce about a billion grains of pollen per season, and the pollen is transported on the wind. It causes about half of all cases of pollen-associated allergic rhinitis in North America. … Ragweed pollen can remain airborne for days and travel great distances, affecting people hundreds of miles away. It can even be carried 300 to 400 miles (640 km) out to sea

Ragweed article, Wikipedia

It’s hard to avoid these pollen grains because they’re so pervasive, but you can be forewarned of a bad pollen day at On the other hand, your nose might know before the website does!

A grain of ragweed pollen (photo from Wikimedia Commons)

Meanwhile, don’t walk past this plant unawares. Here’s what it looks like in a weedy patch.

Ragweed, growing like a weed (photo from Wikimedia Commons)

Know your enemy.

(photos from Wikimedia Commons; click on the captions to see the originals)

(*) Different species of goldenrod have different flower cluster shapes — it’s not always a plume. However tall goldenrod, pictured above, is the one most often called ragweed by mistake.

Fringetree Fruit

Fringetree fruit, 31 August 2019 (photo by Kate St. John)

One advantage of botanizing the same place over and over again is that you get to know what grows where. You remember a plant that draws attention in the spring, forget it in the summer when it’s boring, then notice it again in fall. Because it’s in the same location, you know what it is.

The identity of this dangling blue fruit was a puzzle until I remembered that it’s hanging from the fringetree that put on a floral show in May.

One flower of a fringetree in Schenley Park, 18 May 2018 (photo by Kate St. John)
One flower of a fringetree in Schenley Park, 18 May 2018 (photo by Kate St. John)

Each flower can become a blue fruit.

(photos by Kate St. John)